Calcium containing pyrotechnic compositions for high altitudes



United States Patent 3,261,731 CALCIUM CONTAINING PYROTECHNIC COM- POSITIONS FOR HIGH ALTITUDES Seymour Lopatiu, Dover, N.J., and David Hart, deceased, late of Dover, N.J., by Ruth Hart, executrix, Dover,

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rubber stoppers from the powdered mixture. Thereafter the powdered mixture is packaged or loaded into suitable cartridges for ready use.

Binding agents may be used in conjunction with the NJ. assignors to the United States of America as rep- 5 cqniqosition for i p of improving the strength by resellted by the Secretary of the Army utilizing the following binding agents such as nitrocellu- No drawing Filed June 8,1964Sen No. 373,536 lose lacquer, vinyl acetate alcohol resin, laminae and 4 Cl i (Cl, 149-19) epoxy resins. If the binding agent is utilized it is added to the powdered composition in liquid form and dispersed The invention described herein may be manufactured throughout the composition by means of remote conand used by or for the Government for governmental purtrolled blenders, and after pelletizing the mixture, the poses, without the payment to us of any royalty thereon. binding agent ha-rdens by solvent evaporation or chemical This invention concerns new pyrotechnic compositions reaction. in flares, flashes, photoflash cartridges and bombs de- Variations of the composition may be made in that signed to operate effectively at very high altitudes of 100,- 1 calcium-magnesium and calcium-aluminum alloys are 000 feet and outside the earths appreciable atmosphere deemed satisfactory substitutes for calcium metal powder to a distance of 1000 miles or more. as highly eflicient fuels for high altitude photoflash items The primary object of this invention is to provide pyroand when tested had a much greater light output at 100,- technic compositions which will produce a higher light 000 feet than at sea level. This same result may also be output at these altitudes on rockets and missiles than at attained with compositions containing calcium salts that sea level. are oxidants such as calcium nitrate, calcium perchlorate,

Present pyrotechnic compositions which are generally or additives calcium oxide or calcium fluoride. This inused in flares produce as little as one percent of their sea dicates that calcium, as a metal powder, alloy or salt is level light output at an altitude of 100,000 feet. Photonecessary for the production of superior high-altitude flash compositions also produce only 50% of their sea 25 flashes. level output at 100,000 feet or more. Some choice is also permitted in the selection of oxi- Specifically this invention employs powdered metallic dants in this pyrotechnic composition in that for the calcium together with an oxidizing agent such as potaspotassium per-chlorate there may be substituted the persium perchlorate to form the pyrotechnic composition chlorates of sodium, lithium, strontium or barium, or which on combustion will produce the desired result. the nitrates of potassium, sodium or calcium.

In the preparation of this pyrotechnic composition, con- Some of the results obtained with the various combitrol of the particle size of the ingredients is essential in nations are set forth in the following table:

Total Light, Potassium Ca, Al, Barium Mg, Weight of candle-seconds Perchlorate, percent percent Nitrate, percent Composition,

percent percent grams Sea Level 100,000 ft.

30 40 so 1 231, 000 116, 000 30 10 30 25 190, 000 177,000 30 20 20 22 147, 000 164, 000 30 30 10 20 so, 000 132, 000 60 4o 27, 000 74, 000 46. 5 53. 5 50,000 123, 000 42 5s 60,000 148, 000 65 111,000 183, 000 20 so 103,000 320, 000 10 90 62, 000 263,000 59 90, 000 9, 000 43 28,000 91,000 2 60 60, 000 214, 000 20 so 108, 000 364, 000 10 so 3 10 107,000 343, 000

Standard. 1 NaClO 3 NaNOg.

order to obtain reproducible results. The average particle size of the metallic calcium powder is about 25 microns as measured by the air permeability method, while the average particle size of the oxidizing agent, such as potassium perchlorate, can vary over a large range of 25 to 150 microns, but should be controlled for each composition. Each of the ingredients are then exposed to the atmosphere for a period of less than fifteen minutes to establish a fairly high relative humidity of 75% as a safe upper limit for the succeeding operations of blending and loading. The required percentage weight of each ingredient was dry blended in atmosphere of low humidity at ambient temperatures and pressures and placed in a rubber container together with an equal weight of small rubber stoppers, the latter being added to improve the uniformity of the final blend. The rubber container is sealed by taping the cover, and the container and contents are rotated by remote control for a period of thirty minutes, after which the entire contents are transferred to a No. 16 mesh sieve for the purpose of separating the The table in general indicates, within limits that the trend is toward incrwsing the light output of a fuel-oxidant mixture by increasing the fuel content and calcium in some form is an essential ingredient. Also the weight variation for each composition is due to the variations in their loading densities. The same test vehicle, which was a magnesium Daisy cartridge, was used to evaluate each composition which were loaded to the same volume, and therefore explains the variations in weight of the diflerent compositions.

The present flashes obtained from standard photofiash powders owe their luminosity to grey body radiation, largely of a continuous nature. This continuous type radiation occurs at both sea level and at high altitudes. Since the total energy of a flash is radiated as heat and light and is proportional to the fourth power of the absolute temperature, the reduced temperature of the flashes due the lower pressures at high altitude causes less light to be emitted. Whereas the light output at sea level for the calcium containing compositions is also due essentially 3 v to grey body radiation and at high altitudes the combustion product of calcium (calcium oxide) "has the ability to emit very intense band spectra and it is these intense bands that are responsible for the increased light output at higher levels.

In order to disclose the nature of the present invention, several specific embodiments are described. It should, however, be understood that this is done solely for the purpose of illustrating, by means of concrete examples, the basic principle involved and that such examples are not intended either to delineate the breadth of the invention or to restrict the scope of the appended claims.

What is claimed is:

1. A process for preparing a pyrotechnic composition comprising, grinding separately to a powder 40-90% of metal calcium and 60-10% of potassium perchlorate, exposing the powders to the atmosphere for a period of less than fifteen minutes to establish a humidity of 75% as a safety precaution for succeeding operations, blending the powdered ingredients in a rubber container with a low humidity, adding to the blend an equal weight of rubber stoppers, rotating the rubber container in a sealed condition to mix the powdered material into a uniform blend, removing the rubber stoppers with any suitable sieve and packaging the blended powdered mixture which on combustion will yield a light output at an altitude above 100,- 000 feet more than double that at sea level.

2. A process for preparing a pyrotechnic composition comprising, grinding separately to a powder metal calcium and potassium perchlorate, blending together in a sealed container the powdered constituents for a uniform mixture and packaging the powdered mixture into a vehicle which on combustion of the composition at an altitude above 100,000 feet will yield a higher light output than on combustion at sea level.

3. A process for preparing a pyrotechnic composition comprising, grinding separately to a powder 4090% of metal calcium and '6010% of potassium perchlorate, blending together the powdered constituents in a sealed container for a uniform mixture and packaging the powdered mixture into a vehicle which on combustion of the composition at an altitude above 100,000 feet will yield a light output more than double that emitted by combustion of composition at sea level.

4. A pyrotechnic composition yielding a higher light output on ignition at an altitude over 100,000 feet than on ignition at sea level in which the composition consists of a finely divided mixture of a powdered constituent containing calcium, a powdered oxidizing agent and a powdered binder selected from the group consisting of nitrocellulose lacquer, vinyl acetate alcohol resin, laminac and epoxy resins.

References Cited by the Examiner UNITED STATES PATENTS 2,375,742 5/1945 Kalil et al 149-42 X 2,981,616 4/1961 Boyer 149-37 X 3,094,445 6/1963 Busk et al 149-37 3,098,351 7/1963 Higgins et al 149-42 X BENJAMIN R. PADGETT, Primary Examiner. 

3. A PROCESS FOR PREPARING A PYROTECHNIC COMPOSITION COMPRISING, GRINDING SEPARATELY TO A POWDER 40-90% OF METAL CALCIUM AND 60-10% OF POTASSIUM PERCHLORATE, BLENDING TOGETHER THE POWDERED CONSTITUENTS IN A SEALED CONTAINER FOR A UNIFORM MIXTURE AND PACKAGING THE POWDERED MIXTURE INTO A VEHICLE WHICH ON COMBUSTION OF THE COMPOSITION AT AN ALTITUDE ABOVE 100,000 FEED WILL YIELD A LIGHT OUTPUT MORE THAN DOUBLE THAT EMITTED BY COMBUSTION OF COMPOSITION AT SEA LEVEL.
 4. A PYROTECHNIC COMPOSITION YIELDING A HIGHER LIGHT OUTPUT ON IGNITION AT AN ALTITUDE OVER 100,000 FEED THAN ON IGNITION AT SEA LEVEL IN WHICH THE COMPOSITION CONSISTS OF A FINELY DIVIDED MIXTURE OF A POWDERED CONSTITUENT CONTAINING CALCIUM, A POWDERED OXIDIZING AGENT AND A POWDERED BINDER SELECTED FROM THE GROUP CONSISTING OF NITROCELLULOSE LACQUER, VINYL ACETATE ALCOHOL RESIN, LAMINAC AND EPOXY RESION. 